Happy holidays from the team at Cosmos

We're on a break until January 3, 2018. In the meantime, please enjoy our holiday reading features appearing every day – and, of course, browse our extensive archive of the brightest and best science stories!

The bad science of medical cannabis – Millions of people use cannabis as a medicine. That’s not based on clinical evidence, nor do we know which of the hundreds of compounds in the plant is responsible for its supposed effects. Elizabeth Finkel reports.

How big is the universe?There is no bigger empirical question in astrophysics than how big space is. Cathal O'Connell provides a brief history of ideas about the size and shape of the universe.

Einstein, Bohr and the origins of entanglement – Two of history’s greatest physicists argued for decades over one of the deepest mysteries of quantum mechanics. Today, their successors are opening new fronts in the battle to understand ‘spooky action at a distance’, writes Robyn Arianrhod.

Galleries

Capturing the Earth as art – Since 1996, the Sally Ride EarthKAM program, sponsored by NASA, has enabled school students around the world to remotely point and shoot a special camera on the International Space Station.

Intergenerational contagion: diseases trapped in ice – As global temperatures head north, Arctic permafrost is thawing to unprecedented depths, reanimating a small army of deadly microbes – dormant, in some cases, for millennia – that could rise from the slush to infect humanity.

The microscopic majesty of pollen – It literally gets up the nose of millions of hay fever sufferers, making pollen a distinctly unpopular member of the floral world. But there are many reasons to love these gossamer grains.

What we have learnt by exploring Mars – The Schiaparelli probe made headlines in October 2016 when it crash-landed on Mars. It wasn’t a disaster, though, it was mainly a practice run for the European Space Agency’s next mission to the red planet.

The mystery of meningitis – Meningitis is generally a disease doctors expect to see only in children or young adults. So clinicians’ antennae aren’t up when someone older comes into the surgery sick, writes Norman Swan.